My daughter is an escape artist. Once she is in bed, she takes everything off down to her diaper and falls asleep. This is fine until she "needs" the diaper and wakes up on soaking wet sheets, really cold. Her jammies are of course dry.
Recently, we decided to do something about this. I pulled out my son's 4T jammies. Little N wears a 2T, meaning the 4Ts are a huge on her. I put the jammies on her backwards and flipped the feet around. This worked for a while, until the feet would untwist and she would trip.
The next option was duct tape. This solves the diaper problem. We have resorted to duct taping her diaper shut, putting her in jammies backwards, so she can't get to the zipper, and then a vest on top, also backwards, to further slow her down.